An alarm is triggered and a swarm of drones swoops in, surrounds the building and uses antennas to locate people inside, enabling firefighters to go straight to the stricken individuals. Just in the nick of time – no deaths are recorded. Elsewhere in the city, drones fly back and forth delivering tissue samples from hospitals to specialist labs for analysis, while another rushes a defibrillator to someone who has suffered a suspected cardiac arrest on a football pitch. The patient lives, with the saved minutes proving critical. At the time of writing, drones have already been used in search-and-rescue situations to save more than 880 people worldwide, according to drone company DJI.